One way would be to split the ring into two separate sprites - front and back.
An easy way to keep the z-order is to create one group for the "back" part of the ring, then create the player and finally create a group for the "front" part of the rings.
As long as you create rings in pairs of sprites (back and front), in their correct groups, the z-order will remain.

Hi All!
I just wanted to introduce a game we created called Minako Vs Zombies.
This is a platformer with a story line and a grand finale. If people like it, we plan to make a continuation game and progress the storyline even further.
As a side note, I am an old school C++ developer and was quite resistant to HTML games... but when I was introduced to Phaser I felt like I was home!
What an amazing framework this is. So much can be done in just a few lines of code.
Here is the link to the Google Play store: https://play.google.com/store/apps/details?id=com.studioventdest.minakovszombies
More details can be found here: http://studioventdest.ca/studioventdest/www/#/minako
Web demo of the game: http://minako.studioventdest.ca/
Let us know what you think. Any constructive criticism is more than welcome.
Thanks for taking the time to check it out!

If anybody still is interested in this topic, there is tool that generates physics data as a JSON file... It's called Easy Polygon Marker.
It can be found here:
http://dunceware.com/Products/EasyPolygonMarker.aspx
see the quick start guide here:
http://dunceware.com/Products/EasyPolygonMarker/QuickStart-EasyPolygonMarker.pdf

Hi There,
I decided to try and work with P2 physics and could not find a free tool to generate the JSON file for sprite shapes.
So... I created one
http://dunceware.com/Products/EasyPolygonMarker.aspx
See Quick Start Guide here: http://dunceware.com/Products/EasyPolygonMarker/QuickStart-EasyPolygonMarker.pdf
Please let me know what you think and if anything doesn't seem to work.
Thanks,
Morris